Continuity mistake: When Frosty gets off the train because Karen gets sick, from the magician's view it appears the train is slowing down and is very close to Frosty, but when the shot goes back to the magician, the train appears to be going much faster and is much further away.
Factual error: In the 19th Street Parade, it shows the Budweiser Clydesdales pulling their famous wagon. Even though this movie is set in 1897, Budweiser did not start using Clydesdales until April 1933 when the sons gave their father, August Busch Sr., the owner of Budweiser, a 6 team team of Clydesdales to celebrate the end of Prohibition.
Revealing mistake: Sam is supposedly far away from civilization, but throughout the movie you can see a ski slope in the background. (00:16:05)
Continuity mistake: In the scene where the shipwreck survivors are being rescued by Captain Nemo's divers, Nanette Newman is barefoot as she is carried into the submarine. In the shot immediately following, she is being carried into the sub by a diver and she is wearing full length black boots.
Continuity mistake: When Charlie Brown is doing the dog food for Snoopy, the amount of food in Snoopy's dish changes between the kitchen and the dog house.
Continuity mistake: When the cabbie gets out of his cab, he closes the door, in later shots, you can see the door is open and he's standing between the open door and cab. Some shots show the door closed again.
Continuity mistake: Professor Quigley shows his students a grocery list, and then demonstrates how a computer can be used to make a phone call to the grocer's and place the order by playing a recorded message. However, the grocery items named on the recording do not match the items on the list.